1.2.3 The Lungs and Investigating Lung Function

1.2.3 The Lungs and Investigating Lung Function(a) Tissues and OrgansA tissue is a group of similar cells specialised to carry out the same function.An organ is a structure made up of different kinds of tissue.(b) Relationships Between CellsEpithelial tissue is arranged in single or multi-layered sheets and covers the internal and externalsurfaces of the body. The cells are held together by special junctions and a carbohydrate basedcementing substance between the cells.Epithelium rests on a basement membrane which is a connective tissue matrix containing collagen fibrils.This helps to stabilise and hold the epithelium tounderlying tissues. (c) Cell Structure(d) Photomicrograph of The Lung

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Surface to Area Ratio(f) Gas Exchange SurfaceLarge Surface Area The bronchioles are branched Millions of alveoli in each lung The alveoli are foldedThin Surface Area The squamous cells are very thin Capillary walls are only one cell thickSteep Diffusion Gradient The blood circulation carries oxygenated blood away and brings deoxygenated back Ventilation brings oxygen rich air and air rich in carbon dioxide is removed The surrounding capillaries are very narrow slowing blood flow allowing time for efficient exchange.…read more

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Spirometer(j) Causes of Respiratory Arrest respiratory disorder such as asthma An obstruction in the trachea or bronchi such as food or a small object Overdosing on drugs that suppress the respiratory systemRespiratory arrest may also occur following cardiac arrest.(k) First AidAdultsRoll onto back, lift chin, check for blockages, pinch nose shut, make a seal over their mouth with yours,breath out and check that chest rises, give one breath every 5 seconds.…read more